Sydney in May 2017: a dry month with warm days and a cool finish

Rainfall was below average across Sydney during May, with fewer rain days
and more sunshine than average. Days were warm across the city, with a
cool spell at the end of the month which brought Observatory Hill its
coldest May night since 1999.

A dry end to autumn

Rain was below average across Sydney during May, but not as dry as May
2016

There were nine rain days at Observatory Hill, below the May average
of 13 days, while only two recorded more than 5 mm (average five days)

Rain was recorded across the city on the 20th, while parts of eastern
Sydney recorded falls above 10 mm on the 4th and 15th

Sydney Airport recorded a daily average of 7.4 hours of sunshine,
above the May average of 6.3 hours

A warm month with a cool finish

Daytime temperatures were above average across the city

Overnight temperatures were also above average at Observatory Hill but
closer to average in other areas

Only six days failed to reach 20 °C at Observatory Hill, the
equal fifth-fewest on record (average 18 days)

Temperatures were cool at the end of the month, with Observatory Hill
recording a minimum temperature of 7.1 °C on the 30th, the
coldest May night since 6.6 °C on 16 May 1999, although western
Sydney experienced a colder night in late May
2016

Most values are the precipitation
in the 24 hours to 9 am on the day indicated. Days marked
with → are part of a longer accumulation, which is shown on the
final day.
Values over 100 mm have been rounded to the nearest whole
millimetre.
Days marked with - have a rainfall report of zero; days left blank
have no rainfall report (which often indicates no rain fell).

Notes

The Monthly climate summary, generally published on the first working
day of each month, lists the main features of the weather in Sydney
using the most timely and accurate information available on the date of
publication; it will generally not be updated. More extensive
discussion of significant weather events, along with later information
and data that has had greater opportunity for quality control, will be
presented in the Monthly Weather Review.

This statement has been prepared based on information available at 9
am on Thursday 1 June 2017. Some checks have been made on the data, but
it is possible that results will change as new information becomes
available.

In some situations, some or all of the rainfall is in the form of hail
or snow. In these cases the totals given are for the water equivalent:
the depth of liquid water that results from melting any frozen
precipitation. There can be significant 'undercatch' of snow in strong
winds, meaning the true precipitation can be higher than that reported.

Averages for individual sites are long-term means based on
observations from all available years of record, which vary widely from
site to site. They are not shown for sites with less than 10 years of
record, as they cannot then be calculated reliably.
The median
is sometimes more representative than the mean
of long-term average rain.

The Rank indicates how rainfall this time compares with the
climate record for the site, based on the decile
ranking (very low rainfall is in decile 1, low in
decile 2 or 3, average in decile 4 to 7, high in decile
8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time
as a percentage
of the long-term mean.

Where temperature area averages are mentioned, they are derived from
the ACORN-SAT
dataset.